Magnetism is a fundamental physical property of matter. Matter has measurable magnetic characteristics resulting from an electronic structure of constituent atoms and molecules. When a material is in a steadily applied magnetic field, the material responds with an induced magnetic field that can be measured. The measurement of this magnetic response may be referred to as magnetic susceptibility. The magnetic susceptibility of a material is determined by the strength of the magnetic response induced in the material by application of a magnetic field.
Susceptometers have been developed as a non-invasive method of measuring the magnetic susceptibility of a material. A susceptometer applies a magnetic field to induce a response from the material. This response is evaluated by recording the magnetic flux that the material produces. The susceptometer provides information about the nature of the material based on the evaluation of the magnetic flux. This information is used, for example, to measure hepatic iron stores in patients with iron overload.